| 摘要 |
<p>A resin-coated Al-Zn alloy coated steel sheet is excellent in formability, resistance to chromium dissolution, corrosion resistance, alkali resistance, and paintability, and produced by the following method. That is, a silane coupling agent having amino group, chromium ion and at least one alcohol selected from the group consisting of trihydric alcohol and dihydric alcohol having the number of carbon of 2 to 3 are compounded into an acrylic polymer resin emulsion including carboxyl group and glycidyl group, and having an acid value of 10 to 60. A pH of the resultant mixture is adjusted within a range of 7 to 9 to obtain a chromate containing resin composition. The chromate containing resin composition is applied on an Al-Zn alloy coated steel sheet as a substrate, and then dried to obtain a resin film on the substrate. A compounding amount of the silane coupling agent is within a range of 0.5 to 3.0 wt% with respect to a resin solid component of the acrylic polymer resin emulsion. A compounding amount of the alcohol is within a range of 25 to 150 wt% with respect to the chromium ion. An amount of the resin film is within a range of 0.5 to 3.0 g/m<2>, and a content of chromium ion in the resin film is within a range of 5 to 50 mg/m<2>.</p> |
